I have a big piece of foam board that I was using for DWC Aquaponics. I cut out a chunk and put it in the mill. The part was done _an hour_ later. In hindsight, I set the mill to cut parallel passes with a tiny stepover amount.

I'll post the .nc files shortly.

EDIT: Here is the .nc file for a full depth slow Pencil cut around the outside of the part. This is designed for foam. It will likely break something if you try it in anything more substantial than foam.